The present invention relates generally to multimode sensors, and in particular to a multimode short wavelength infrared (SWIR) and radio-frequency (RF) seeker.
Airborne platforms, such as airborne munitions, may include sensors. One such sensor, for example, is a seeker. Seekers may be configured to receive electromagnetic radiation, often in the visible or infrared spectrum, through an aperture and perform image detection that may be utilized for guidance and navigation of the munition. Another seeker function that may be utilized is semi-active laser (SAL) detection. In SAL detection, a beam of laser radiation is directed at a target. The seeker detects the radiation reflected from the target and adjusts the munition's navigation accordingly. Imaging and SAL detection seekers are often implemented in the “nose” of the munition for ease in receiving radiation in the direction of flight and guiding the flight path.
Airborne objects may also include radio-frequency (RF) sensors. RF sensors transmit and receive electromagnetic energy in the RF spectrum through an aperture. RF sensors may be utilized as, among other things, height-of-burst (HOB) sensors. HOB sensors employ active radar to measure the range from the munition to the target object in order to command payload initiation at a predetermined distance from the target. Ideally, the RF sensor would also be implemented at the “nose” of the munition for optimal sensor performance and payload initiation functions. Some munitions include multiple sensors utilizing multiple respective apertures under a common radome. Other munitions locate the seeker in the “nose” of the munition and locate the RF sensor, for example, within the structure of the munition having an RF aperture on an outer surface. Each of these implementations has disadvantages, including increased cost, difficult packaging and suboptimal performance. It is desirable to create a sensor that utilizes a common aperture to act both as a seeker, as well as an RF antenna.